Field of Invention
This invention relates to a method for transferring cargo between an ocean-located unit and a vessel, that is to say from the unit to the vessel or vice-versa, by way of a loading crane or derrick with associated winch especially under conditions of heavy wave movement at sea, as well to apparatus for carrying out such a method.
By the expression "ocean-located unit" hereinafter is meant a land installation which borders the ocean and various types of work platforms, such as bore rigs and the like, arranged on the ocean together with different types of ocean-going vessels. On transferring cargo between a freighter and a land installation as well, in practice, as at work platforms, it is necessary to take account of the wave movement of the freighter, while on transferring cargo between two freighters, it is necessary to take into account the wave movements of both freighters, that is to say the relative wave movement between the freighters.
On loading and unloading a vessel at an ocean-located unit, significant problems occur if the wave movements are particularly heavy since the loading and unloading work is extremely dangerous, especially for personnel who work on the deck of a freighter. In addition, there is the risk of damaging the cargo, the unloading and loading equipment as well as the vessel itself. There has arisen an increasing need of being able to load and unload freighters during virtually arbitrary weather conditions, especially in connection with oil search and extraction work in oceanic zones and with heavy wave movements at sea.